Electric fuse



B. K. SMITH ELECTRIC FUSE Sept. 12, 1933.

Filed Oct. l, 1930 2 Sheets-Sheet l B. K. SMITH ELECTRIC FUSE Sept. l2, 1933.

Filed OGb. l, 1930 2 SheebS-She6t 2 'IIIIIIII'II ulllll ...l I.

Patented Sept. 12, 1933 ELECTRIC FUSE Bedford K. Smith, Alexandria, Va. I

Application October 1, 1930. Serial No. 485,731

f 2 Claims.

(Granted under the Act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) My invention relates broadly to protective electric fuses and more particularly to a renewable fuse for the protection of electric circuits.

Oneof the objects of my invention is to provide a simplied construction oi renewable fuse for protecting electric circuits which is inexpensive in manufacture and production and which may be refilled vwithin minimum time without a large degree of skill.

Another object of myA-invention is to provide a construction of renewable electric fuses wherein the parts which house the fuse may be displaced one relative to another for-receiving a renewal fuse and thereafter closed upon each other for housing the renewal fuse.

Still another object of my invention is to provide a simplified construction oi renewable fuse having an insulating housing with parts arranged to slide longitudinally one with respect fy Y to another for housing a renewal fuse and establish electrical connection with opposite ends thereof.

A further object of-my invention is to provide a construction of renewable fusekin which parts of thefuse may be assembled or disassembled by hand without'the employment of tools. v

A still further object of my invention is to provide a construction of renewable fuse wherein the enplosive'effects may be dissipated longitudinallyor` the vcasing through ports provided in the end caps without producing destructive effects tendingto laterally tear ordisplace the parts of the fuse cartridge.l

Other and iuther objects of my invention rei sidein the design of a renewable fuse set forth in the specification hereinafter following `by reference'to the accompanying drawings, in which:

VFigure 1 isa longitudinal cross-sectional view taken through one'form of the fuse of my invention' Fig. i). illustrates the fuse container having one side ofV the-housing thereof removed; Fig. 3 is a plan view oi' one portion of the fuse housing illustrated in Fig. 2; Fig. 4 is a cross-sectional .view taken through the renewable iuse structure on'linei4-4 of Fig. 1; Fig. 5 is a perspective View of the fuse employed in the fuse housing of my invention; Fig. 6 illustrates a modiiied form of renewable vfuse construction in which a screw plug member may be screwed into a receptacle for the connection of the fuse in a protective circuit. Fig. 'l is a cross-sectional view on line 7 7 ofthe fuse construction illustrated in Fig. 6; ;`Fig.8 is a detailed fragmentary view of a further modied form of renewable fuse construction; Fig. 9 is any end view of the modified form portion 2 has a rivet member 6 extending thereoi fuse construction illustrated in Fig. 8; Fig. 10

is a cross-sectional View through another modiiied form of fuse embodying my invention; Fig.

11 is a plan View of the fuse housing illustrated in Fig. showing the parts o1" the fuse housing 60 open for the reception of a renewable fuse; Fig.

12 is an end view of the form of fuse construction illustrated in Figs. 10 and 11; Fig. 13 is a crosssectional View through the fuse vhousing on line 13-13 of Fig. 10; Fig. 14 is a cross-sectional View 65 through a further modified form of renewable fuse embodying the principles of my invention; Fig. 15 is a side elevation of the construction of fuse illustrated in'Fig. 14; Fig. 16 is an end view of the renewable fuse illustrated in Figs. 14 and 70 15; and Fig. 17 is a cross-sectional view through the renewable fuse housing of the construction shown in Figs. 14, v15 and 16, in the process of assembly or disassembly.

My invention is directed lto a simplified construction of renewable fuse plug capable of economic manufacture on a quantity production basis and adapted 'to be readily refilled after rupture of the fuse. I havehad considerable experience with many differenttypes of renewable fuse plugs. Heretoiore manufacturers in endeavoring to produce a renewable fuse plug have rendered the construction thereof so elaborate that the lling and refilling operation requires the use of tools and the expenditure of a substantial time interval. In my construction of renewable fuse plug, the parts are reduced to a minimum and the construction thereof so simplied that a renewal operation may be eilected without employing tools. The renewaloperation in the construction oi fuse plug of' my invention requires only a brief interval of time for an operation which maybe performed by a simple sliding movement. i

VReferring to the drawings in more detail, reference characters 1 and 2 designate cooperatively related insulating housings-of substantially semicircular cross-section with their diametrical portions aligned one with respectto the other. The insulating portions l and 2` of the housing are aligned to provide a central channel 14 extending longitudinally therebetween with the walls of the channel formed by the two aligned portions l. and 2 as represented at 14a and 14h End caps 3 and 4 are adapted to slip longitudinally over the 'ends of the housing portions 1 and 2 for securing the housing portions in position. The housing portion 1 has a rivet member 5 extending therethrough adjacent one end while housing through adjacent the opposite end. End cap 3 establishes electrical connection with one end of rivet member 5. An end cap 4 establishes electrical connection with one end of rivet member 6. In this way there is presented two opposite terminals within the channelway 14 across which the fusible element 17 extends. The end cap 3 is secured in position with respect to section 2 of the housing by means of pin 7. End cap 4 is secured in position on insulating section 1 by means of pin 8. Each end cap 3 and 4 has an inwardly directed conductive extension or brush member 11 and 12, respectively. Brush 11 is secured to end cap 3 by rivet 9. Brush 12 is secured to end cap 4 by rivet 10. A suitable recess indicated at 2c is provided in the end of section 2 to enable the end cap 3 to be slipped to a secure position over the end of the housing with one portion thereof in abutment with the end of insulating section l. The insulating section 1 is provided with a suitable recess indicated at 1c to allow the head of rivet 10 to extend therein when cap 4 is slipped over the ends of the insulating housing formed by members 1 2. The housing 2 is slotted at 2a to receive the downwardly turned portion 17a of the fuse 17. When the fuse is assembled, brush 12 presses one end of fuse 17 into engagement with the end of conductive rivet 6 while brush 11 presses the opposite end of fuse 17 into engagement with the end of rivet 5. To enable fuse 17 to be inserted in either direction in the holder, section 1 is also provided with a recess 1a to receive the end 17a of the fuse. In order to guide the housings 1 and 2 into proper alignment, one edge of housing 2 is provided with a longitudinally extending groove 15a while the opposite edge is provided with an upwardly extending longitudinal projection 16. The aligned section 1 is provided with a longitudinally extending groove 16a to receive the projection 16 of section 2 and at the opposite side is provided-with a projection 15 which enters the groove 15a in section 2 of the insulating housing. The end of section 2 is suitably tapered as designated at 2b to facilitate the longitudinal movement of the end cap 4 over the insulating housing. vSimilarly the end of section 1 is tapered as represented at lb to facilitate the entrance of section 1 of the housing into the end cap 3. It will be seen that in the assembly of the fuse, the fuse element 17 is rst inserted in the channel 14 with the end 17a entering the slot 2a retaining the fuse in position as the parts of the housing 1-2 are slipped longitudinally with respect to each other in the position shown in Fig. 1. If desired the fuse element 17 may be inserted with the end 17a thereof extending into recess 1a in the insulating section l. That is to say, the fuse element 17 is reversible in position and may be mounted within channelway 14 in either direction. When the Vportion 1 of the housing has been Yslipped endwise with respect to portion 2 of the housing to the position shown in Fig. 1, the parts are retained in assembled relation by the frictional grip between the insulating housing portions 1 and 2 and the interior walls of the caps 3 and 4. The caps 3 and 4 are suiciently resilient to enable a tight t of the coacting parts of the assembled fuse cartridge to be maintained. Ports 3a and 4a are provided centrally of the end caps 3 and 4, respectively in alignment with the channelway 14 to permit the dissipation of destructive pressures or gases arising from the blowing of a fuse. The gases are allowed to pass longitudinally out of the passageway 14 through the ports 3a and 4a and thus prevent deterioration or destruction of the casing of the renewable fuse by lateral forces which would normally tend to injure the parts of the cartridge, the two ledges 15 and 16 forcing the gases to be nally dissipated through the apertures in the end caps by virtue of the resistance to the seepage of the gases between the ledges l5 and 16 and the associated grooves 15a and 16a. The danger of fire on rupture of the fuse element is practically eliminated in the construction of my invention.

In the modified form of my invention shown in Figs. 6 and 7, a screw base 24 is provided on an insulating end portion 20 which extends integral with the cylindrical insulating portion shown at 19. A central contact 21 in insulating base 20 connects to a contact plate 22 extending in alignment with the face of the channelway 27 of upwardly projecting portion 19. The screw portion 24 is connected through conductor 23 to a plate member 23a on the face of the channelway 27 in the insulating portion 19. A semi-circular insulating portion 18 constructed for cooperative alignment with the insulating portion 19 carries a pair of brush members indicated at 18a and 18h aligned with plate member 22 and conductive member 23a in the channelway 27 across which the renewable fuse 25 connects. The brushes 18a and 18h serve to press the ends of the fuse 25 into electric connection with the conductive plate 22 and the conductive plate 23a thereby maintaining the fuse in an electrical circuit between the center plug 2l and the screw base 24. I provide cooperatively aligned grooves and projections in the parts 18 and 19 in a manner similar to the projection explained in Figs. 1-4. The insulating portion 18 of the renewable fuse is provided with end cap 26 connected thereto by means of pin 26a. By grasping the end cap 26 the insulating portion 18 may be longitudinally withdrawn from the socket portion 20 exposing the channelway 27 and enabling a renewal fuse 25 to be disposed therein and the fuse cartridge thereafter closed. The port 26h in the end cap 26 is aligned with the channelway 27 enabling the discharge of destructive pressures or gases without injury to the parts of the fuse cartridge proper.

In Figs. 8 and 9 I have shown a modiiied form of end cap 30 in engagement with one of the portions 2 of the housing. The end cap 30 carries brush member 31 which projects into the channelway 14 and provides means for securing the fuse in position within the channelway. The blade 32 is adapted to slip between pairs of oppositely connected jaw contacts. Connection is established between end cap 30 and brush 31 through a rivet member as shown.

In Figs. 10-13 I have shown a form of renewable fuse in which the insulating housing portions 1 and 2 are pivoted one with respect to the other. In this construction an end ferrule shown at 33 is divided into parts 33a and 33b secured to the insulating housings 1 and 2 and pivotally connected as shown at 34. The end cap 35 is removable from the ends of casing portions 1 and 2 enabling the casing portions to be swung apart with respect to each other as represented in Fig. 11. The lower insulating casing 2 provides a support for the fuse 36 which contacts with rivet members 37 and 38 at opposite ends of the fuse completing connection to the end ferrule 33 and end cap 35. The brush members 39 and 40 carried by the portion 33h of end ferrule 33 and the end cap 35 serve to press the fuse 36 into electrical connection with the rivets 37 thereby maintaining the fuse in position for completing the electrical circuit therethrough. `A chamber 41 is provided in the upper portion 1 and gases and excess pressures are relieved from this chamber through ports 42 in the end ferrule and end cap as indicated. The edges of insulating portions l and 2 are aligned by offset portions represented at 43 and 44 providing a tight housing for the fuse when the hinged parts are brought into alignment with each other. As represented in Figs. 14-1'7 the housing for the renewable fuse may comprise parts l and 2 which are slipped horizontally with respect to each other to form a closed housing. In this construction the end caps are provided with interengaging joints represented at 45 and 46 which slide endwise enabling the parts to be aligned one with the other by a quick horizontal movement in a lateral direction. Fig. l'l explains the manner in which the offset portions 44 and 43 align with each other in providing a tight casing. When the fuse 36 is burned out any pressures built up in channelway 41 are dissipated through ports 42.

The renewable fuse of my invention has been found extremely practical in its construction and practical in its operation. While I have described my invention in certain preferred ernbodiments I desire that it be understood that modifications may be made and that no limitations upon my invention are intended other than those imposed by the scope of the appended claims.

The invention herein described may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon.

ling a pair of coacting separable What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. An electric fuse comprising a container having a pair of separable parts, an internal channelway defined by the separable parts when disposed in alignment one with the other, said separable parts being transversely recessed adjacent opposite ends thereof and having terminals disposed adjacent the transverse recesses and a renewable fuse member having an angularly disposed end adapted to enter a selected one of said transversely recessed portions of said separable parts within said channelway and means for maintaining said fuse member in electrical connection with said terminals.

2. An electric fuse comprising a casing includparts having laterally extending recesses adjacent each end thereof, an end cap secured to one end of each of said separable parts and shaped to receive the end of the coacting separable part, a longitudinally extending channelway defined by the coacting separable parts, connecting members extending through remote from the end thereof to which the associated end cap is secured in positions adjacent each of said recesses, a brush member carried by each of said end caps and projectable into the channelway, and a renewable fuse extending through said channelway with one end thereof anchored in the laterally extending recess adjacent one end of one of said separable parts and maintained in electrical connection with said connecting members under guidance of each of said brush members.

BEDFORD K. SMITH.

each of said separable parts 1 

